/Engine/Plugins/Runtime/MeshModelingToolset/Source/ModelingComponents/Public/Selection/GeometrySelector.h
The OnGeometryModified delegate will fire if the geometry of the Selector's Target Object is modified. For example if aUDynamicMeshis edited, OnGeometryModified will be broadcast.
[FOnGeometryModified](API\Plugins\ModelingComponents\Selection\IGeometrySelector\FOnGeometryModified) & GetOnGeometryModifed()